Monoclonal antibodies to dopaminergic (D2) and serotoninergic (S2) receptors of the central nervous system will be made using the strategy of idiotype: anti-idiotype molecular mimicry. This strategy employs an antibody (idiotype) directed against D2 or S2 antagonists (ligands) to act as a "mold" for the subsequent production of an anti-idiotype antibody which can constitute an "internal image" of the anti-ligand binding sitem and thereby mimic, in molecular terms, the original ligand. A collection of monoclonal antibodies to the dopaminergic ligands, haloperidol and pimozide, have been produced and subsequent anti-idiotype antibodies are currently being tested. These receptor binding antibodies will be used in receptor characterization, localization and purification studies. These studies will provide valuable information tools for the study of idiotype-anti-idiotype mimicry and the role of anti-receptor antibodies in nervous system diseases.